How are guides researched and sourced?
We use primary sources only: peer-reviewed research, legislation, UK regulators and public bodies, and registries of planned trials.
For each guide we work from a fact-pack, which is a list of dated facts where each one has a source link, the publisher, a short verbatim quote checked against the text we fetched, and a note of how strong the evidence is. Our current fact-pack holds 108 such facts.
If a fact is not in the fact-pack, we do not state it, and where we looked and found nothing we say so, for example “we found no trials of injected NAD+ for this”.
The sources we draw on include:
- peer-reviewed papers and systematic reviews, usually via PubMed;
- legislation on legislation.gov.uk and guidance from the MHRA, the Care Quality Commission, Healthcare Inspectorate Wales, Healthcare Improvement Scotland and the Nursing and Midwifery Council;
- rulings and codes from the Advertising Standards Authority and the Committee of Advertising Practice;
- NHS and NICE pages, and clinical trial registries.
Newspaper reports are secondary sources. When we use one, we label it as reporting, for example “reported by The Observer in February 2025”, and we do not state it as settled fact.
Some items in our research are marked as not to be stated as fact, such as a newspaper’s own statement about a product’s licensing status, and we leave those out or attribute them.
How do we rate evidence?
We rate each claim as unproven, early, mixed or established, following how strong the underlying studies are.
| Rating | What it means on this site |
|---|---|
| Unproven | We found no human trials of the injected form for this claim, or only evidence from other forms or settings that does not show an effect. |
| Early | Small human studies of the injected form exist, but they are too small or uncontrolled to rely on. |
| Mixed | Studies disagree, or the findings differ between tissues, groups or methods. |
| Established | Consistent findings from well-conducted human trials or systematic reviews. |
A rating describes the evidence, not you, and it is not a recommendation for or against anything.
Who writes the guides?
The guides are written by the NAD Injections editorial team, and every page shows that byline and the date it was last updated.
We re-date a page only when it has genuinely been changed, not to look fresh.
We do not name clinics in our guides, and we do not reproduce clinics’ claims, product names or marketing.
Is there a clinical reviewer?
No, the pages have not been clinically reviewed.
We intend to add a named clinical reviewer, and until we have done so no page will say or imply that a clinician has checked it.
You can read more on our about page.
How is AI used?
We use AI to help draft pages, and people on the editorial team edit what it produces and check it against the sources.
AI is not used to invent facts, and anything it drafts that cannot be traced to a source in the fact-pack is removed.
Is there any paid influence?
No, nobody pays for what a guide says, and no payment affects a listing.
Listings are free. We do not accept payment to add, remove, rank or reword anything in a guide, and we do not publish reviews or clinic marketing claims.
How often are guides updated?
We re-check a guide when a source changes, when a reader reports an error, or when we add new research, and each page shows when it was last updated.
Clinic listings are handled separately, and we aim to re-verify them every 90 days, as explained in how we verify listings.
How do I report an error?
Email editor@nadinjections.co.uk with the page address, what you think is wrong and, if you can, a link to a source, or use the contact page.
When we confirm an error we correct it and update the date shown on the page.
This page is general information, not medical advice. Speak to your GP or a registered prescriber about your own health, and see our medical disclaimer.